Sec. 73.1030  Notifications concerning interference to radio astronomy, 
          research and receiving installations.

    (a) Radio astronomy and radio research installations. In order to 
minimize harmful interference at the National Radio Astronomy 
Observatory site located at Green, Pocahontas County, West Virginia, and 
at the Naval Radio Research Observatory at Sugar Grove, Pendleton 
County, West Virginia, a licensee proposing to operate a short-term 
broadcast auxiliary station pursuant to Sec. 74.24, or an applicant for 
authority to construct a new broadcast station or for authority to make 
changes in the frequency, power, antenna height, or antenna directivity 
of an existing station within the area bounded by 39 deg.15' N on the 
north, 78 deg.30' W on the east, 37 deg.30' N on the south, and 
80 deg.30' W on the west shall, at the time of filing such application 
with the FCC, simultaneously notify the following:

    Interference Office, National Radio Astronomy Observatory, P.O. Box 
2, Green Bank, West Virginia 24944, Telephone: 304-456-2011.


The notification shall be in writing and set forth the particulars of 
the proposed station, including the geographical coordinates of the 
antenna, antenna height, antenna directivity if any, proposed frequency, 
type of emission and power. In addition, the applicant shall indicate in 
his application to the FCC the date notification was made to the 
observatory. After receipt of such applications, the FCC will allow a 
period of 20 days for comments or objections in response to the 
notifications indicated. If an objection to the proposed operation is 
received during the 20-day period from the National Radio Astronomy 
Observatory for itself or on behalf of the Naval Radio Research 
Observatory, the FCC will consider all aspects of the problem and

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take whatever action is deemed appropriate.
    (b) Radio receiving installations. Protection for Table Mountain 
Radio Receiving Zone, Boulder County, Colorado: Applicants for a station 
authorization to operate in the vicinity of Boulder County, Colorado 
under this Part are advised to give due consideration, prior to filing 
applications, to the need to protect the Table Mountain Radio Receiving 
Zone from harmful interference. These are the research laboratories of 
the Department of Commerce, Boulder County, Colorado. To prevent 
degradation of the present ambient radio signal level at the site, the 
Department of Commerce seeks to ensure that the field strengths of any 
radiated signals (excluding reflected signals) received on this 1800 
acre site (within the area bounded by 40 deg.09'10'' N Latitude on the 
north, 105 deg.13'31'' W Longitude on the east, 40 deg.07'05'' N 
Latitude on the south, and 105 deg.15'13'' W Longitude on the west) 
resulting from new assignments (other than mobile stations) or from the 
modification of relocation of existing facilities do not exceed the 
following values:

                                                                        
------------------------------------------------------------------------
                                                              Power flux
                                                   Field      density in
                                                strength in   authorized
                Frequency range                  authorized   bandwidth 
                                                 bandwidth    of service
                                                 of service   (dBW/m\2\)
                                                   (mV/m)        \1\    
------------------------------------------------------------------------
Below 540 kHz.................................           10        -65.8
540 to 1700 kHz...............................           20        -59.8
1.7 to 470 MHz................................           10     \2\-65.8
470 to 890 MHz................................           30     \2\-56.2
Above 890 MHz.................................            1     \2\-85.8
------------------------------------------------------------------------
\1\ Equivalent values of power flux density are calculated assuming free
  space characteristic impedance of 376.7=120 ohms.                     
\2\ Space stations shall conform to the power flux density limits at the
  earth's surface specified in appropriate parts of the FCC rules, but  
  in no case should exceed the above levels in any 4 kHz band for all   
  angles of arrival.                                                    

    (1) Advance consultation is recommended particularly for those 
applicants who have no reliable data which indicates whether the field 
strength or power flux density figures in the above table would be 
exceeded by their proposed radio facilities (except mobile stations). In 
such instances, the following is a suggested guide for determining 
whether coordination is recommended:
    (i) All stations within 2.4 km (1.5 statute miles);
    (ii) Stations within 4.8 km (3 statute miles) with 50 watts or more 
effective radiated power (ERP) in the primary plane polarization in the 
azimuthal direction of the Table Mountain Radio Receiving Zone;
    (iii) Stations within 16 km (10 statute miles) with 1 kW or more ERP 
in the primary plane of polarization in the azimuthal direction of Table 
Mountain Receiving Zone;
    (iv) Stations within 80 km (50 statute miles) with 25 kW or more ERP 
in the primary plane polarization in the azimuthal direction of Table 
Mountain Receiving Zone.
    (2) Applicants concerned are urged to communicate with the Radio 
Frequency Management Coordinator, Department of Commerce, Research 
Support Services, NOAA R/E5X2, Boulder Laboratories, Boulder, CO 80303; 
telephone (303) 497-6548, in advance of filing their applications with 
the Commission.
    (3) The Commission will not screen applications to determine whether 
advance consultation has taken place. However, applicants are advised 
that such consultation can avoid objectimns from the Department of 
Commerce or proceedings to modify any authorization which may be granted 
which, in fact, delivers a signal at the site in excess of the field 
strength specified herein.
    (c) Protection for Federal Communications Commission monitoring 
stations. (1) Applicants in the vicinity of a FCC monitoring station for 
a radio station authorization to operate new transmitting facilities or 
changed transmitting facilities which would increase the field strength 
produced over the monitoring station in excess of that previously 
authorized are advised to give consideration, prior to filing 
applications, to the possible need to protect the FCC stations from 
harmful interference. Geographical coordinates of the facilities which 
require protection are listed in Sec. 0.121(c) of the FCC rules. 
Applications for stations (except mobile stations) which will produce on 
any frequency a direct wave fundamental field strength of greater than 
10 mV/m in the authorized bandwidth of service (-65.8 dBW/m\2\ power 
flux density assuming a free space characteristic

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impedance of 120  ohms) at the referenced coordinates, may be 
examined to determine extent of possible interference. Depending on the 
theoretical field strength value and existing root-sum-square or other 
ambient radio field signal levels at the indicated coordinates, a clause 
protecting the monitoring station may be added to the station 
authorization.
    (2) In the event that calculated value of expected field exceeds 10 
mV/m (-65.8 dBW/m2) at the reference coordinates, or if there 
is any question whether field strength levels might exceed the threshold 
value, advance consultation with the FCC to discuss any protection 
necessary should be considered. Prospective applicants may communicate 
with: Chief, Compliance and Information Bureau, Federal Communications 
Commission, Washington, DC 20554, Telephone (202) 632-6980.
    (3) Advance consultation is suggested particularly for those 
applicants who have no reliable data which indicates whether the field 
strength or power flux density figure indicated would be exceeded by 
their proposed radio facilities (except mobile stations). In such 
instances, the following is a suggested guide for determining whether an 
applicant should coordinate:
    (i) All stations within 2.4 kilometers (1.5 statute miles);
    (ii) Stations within 4.8 kilometers (3 statute miles) with 50 watts 
or more average effective radiated power (ERP) in the primary plane of 
polarization in the azimuthal direction of the Monitoring Stations.
    (iii) Stations within 16 kilometers (10 statute miles) with 1 kW or 
more average ERP in the primary plane of polarization in the azimuthal 
direction of the Monitoring Station;
    (iv) Stations within 80 kilometers (50 statute miles) with 25 kW or 
more average ERP in the primary plane of polarization in the azimuthal 
direction of the Monitoring Station;
    (4) Advance coordination for stations operating above 1000 MHz is 
recommended only where the proposed station is in the vicinity of a 
monitoring station designated as a satellite monitoring facility in 
Sec. 0.121(c) of the Commission's Rules and also meets the criteria 
outlined in paragraphs (b) (2) and (3) of this section.
    (5) The Commission will not screen applications to determine whether 
advance consultation has taken place. However, applicants are advised 
that such consultation can avoid objections from the Federal 
Communications Commission or modification of any authorization which 
will cause harmful interference.

[ 43 FR 32782 , July 28, 1978, as amended at  44 FR 77167 , Dec. 31, 1979; 
 47 FR 9221 , Mar. 4, 1982;  50 FR 39003 , Sept. 26, 1985;  52 FR 25867 , July 
9, 1987;  52 FR 36879 , Oct. 1, 1987;  52 FR 37789 , Oct. 9, 1987;  56 FR 64872 , Dec. 12, 1991;  61 FR 8477 , Mar. 5, 1996]